'Building the atomic clinic': nuclear research in medicine after the Second World War - an introduction.

This introduction to the special issue re-examines the emergence of nuclear medicine within a global and transdisciplinary framework. Moving beyond canonical narratives centred on technical breakthroughs and early U.S. developments, it highlights the field's development through three analytical lenses: science diplomacy, transdisciplinarity, and socio-political impact. We argue that nuclear medicine took shape not only through innovations in physics and clinical practice, but also through international cooperation, geopolitical agendas, and the negotiation of public expectations. By tracing the circulation of knowledge, radioisotopes, and infrastructure across diverse regional contexts - from Sweden and Taiwan to India and Belgium - it sets the stage for a rethinking of nuclear medicine as a product of intersecting scientific, political, and societal forces during the Cold War and beyond.